1. Field of the Invention
The invention relates generally to a rock drill and more specifically a rock drill for, for example, a hammer drill in accordance with the preamble of claim 1.
2. Discussion of the Background
Rock drills having sintered carbide cutting tips are used for producing bore holes in concrete, masonry, rock or the like. In order to reduce loading and hence the wear of the sintered carbide cutting tip arranged transversely in the drill head, so-called cross-bits have been disclosed, having a main cutting tip extending over the entire diameter of the drill head and sloping in the shape of a roof, and secondary cutting tips arranged transversely to said main cutting tip. A drill of this kind is illustrated, for example, in U.S. Pat. No. 2,673,716, in particular FIG. 2. According to another embodiment in accordance with U.S. Pat. No. 1,106,966, the cruciform cutting tips can also be formed by two tips arranged perpendicular to one another and having corresponding slots.
As illustrated in the first-mentioned US patent, the secondary cutting tips are composed of two parts which, when assembled, would produce a symmetrical, roof-shaped cutting tip. Thus the point of each secondary cutting tip, said point pointing in the drill feed direction, is arranged in as close proximity as possible to the main cutting edge to ensure a continuous transition (U.S. Pat. No. 2,673,716, FIG. 3).
In copending application Ser. No. 07/765.092 filed Mar. 7th, 1988 (Inventor: Bernhard Moser), it was to this end proposed that the points of the secondary cutting tips should be ground down somewhat in order to set back these secondary cutting tips with respect to the main cutting tip in the immediate vicinity of the latter.
DE No. 3,544,433-A1 furthermore discloses a drilling tool having a main cutting edge, passing through the drill head diameter, as well as additional cutting pins which are arranged in radially eccentric fashion.